1. Field of the Invention
The present invention relates to a communication system, and more particularly, to a communication system for providing prepaid communication service over network.
2. Description of the Related Art
Among a diversity of recent communication services, prepaid services have become widespread. Prepaid portable telephone is an example of voice communication-related prepaid service. To use a prepaid portable telephone, a fixed amount of money needs to be paid in advance, and when the charge for calls reaches the amount paid, the portable telephone permits no further calls. This type of portable telephone is widely used by underage people as a precaution against overuse as well as by people who find the basic charge too expensive because of infrequent use.
Also, service called BitCash is an example of prepaid service on the Internet that takes charge of accounting of Web pages, selling of image data, etc. To use this service, the user first buys a prepaid card at a store and scratches a silver film of the card to expose a password hidden thereunder. When utilizing a service of a member store, the user has only to enter the password. The user can enjoy services until the balance of the prepaid card comes to zero.
Meanwhile, services based on IMT-2000, whose standardization had been aimed to be completed in the year 2000, will be launched as next-generation mobile communication services. IMT-2000 is multimedia mobile communication system capable of communications using a maximum of 2 GHz band as determined by the ITU.
With the provision of IMT-2000 services, the function of mobile telephone is expected to be enhanced such that while making a telephone call, the user can access a website on the Internet or download motion picture content, thus widening the application of mobile telephone.
However, in conventional communication systems for providing prepaid services such as those described above, control performed permits only the situation where the user receives a single prepaid service at a time. No efficient control procedure has been established yet for the user's multi-call to prepaid services (simultaneous access calls to multiple prepaid services).
Let it be assumed, for example, that with a portable telephone connected to a personal computer, the user makes a telephone call over a voice network and then wishes to download content on the Internet over a packet network, by utilizing prepaid service provided by a carrier A.
In such cases, since multi-call is not taken account of on the part of the server , all of the balance of prepayment is reserved for the first-requested telephone service via the voice network.
Accordingly, although a request is received thereafter from the packet network, it is not possible to provide a prepaid service over the packet network (there is no control procedure for appropriating the user's balance to another prepaid service provided by the carrier A, and moreover, the manner of how the balance is to be allotted to a plurality of prepaid services is not established).
Thus, the conventional prepaid services are unable to cope with forthcoming multimedia mobile communication environments such as IMT-2000. Accordingly, there has been a strong demand for a prepaid service system which permits the user to start a plurality of prepaid services at the same time and thus can provide high-quality services.